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Home > Metro network trends: Deploying next-gen Ethernet services |
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In this Telecom Insights guide, Nemertes Research analyzes the "why" behind the increasing enterprise demand for next-generation Ethernet networks, as well as the standards and technology needed to architect them. Beyond the research, looks at how carriers can position Ethernet and VPLS services effectively to speak to business needs. In this series:
Ethernet service deployment is skyrocketing, and specifically, metro Ethernet services for enterprises are in highest demand. To prove the point, 73% of Nemertes Research benchmark participants are deploying Ethernet-based services, up from just 52% a year ago. Of the various types of Ethernet services, metro Ethernet is the most popular: 63% of research participants deploy it, typically linking to large sites and data centers. Why the specific metro Ethernet interest? Two main reasons. First, bandwidth: Ethernet services typically deliver some of the highest-available bandwidth in the WAN. Second, simplicity: Ethernet services are often plug-and-play. The single biggest drawback to Ethernet services? Lack of availability. "I'd use more of it if I could get it," is the common refrain. One reason providers are slow to deploy Carrier Ethernet (relative to its popularity) is that for carriers, it often represents a radical departure from their existing architectures. Service providers continue to depend on traditional SONET/SDH-based access, metro and transport technologies, even as they watch demand increase for IP and Ethernet. That means they're managing separate transport hardware and provisioning systems to handle both their legacy networks and the new generation of packet-transport protocols that include Ethernet. The current crop of Ethernet services is defined to run over multiprotocol label switching (MPLS). But from the carrier perspective, turning up new customers on MPLS-based services like Ethernet requires a complex set of steps involving multiple different operational support systems (OSS). Carrier Ethernet standards designed to create single control plane To streamline deployment and management of these new services, carriers are seeking a way to merge their Layer 1, 2 and 3 operations and management infrastructures so they can operate a single control plane for provisioning. Two emerging specifications seek to do exactly that:
The benefits of MPLS-TP. MPLS-TP is essentially an MPLS extension based on the concept of extending MPLS resiliency and provisioning mechanisms to Ethernet via a new transport-focused profile. With MPLS-TP, carriers can mix and match circuit or packet-based services in the same network, using a single control plane and operational support system (OSS) for service provisioning. Perhaps MPLS-TP's most important quality is that it applies circuit-switching-like functionality to MPLS, treating MPLS label switch paths as dedicated circuits. This approach enables operators to define bi-directional paths (same path forward and backward), eliminating the LSP (label switch path) merging capability of MPLS, whereby packets going to the same destination can be merged into a single LSP. By eliminating LSP, MPLS-TP enables providers to isolate customer traffic into separate end-to-end virtual circuits. In addition, MPLS-TP eliminates the need for IP at the end of the LSP by extending the label all the way out to the end device in a path. This allows service providers to eliminate the need to configure IP services on edge devices, instead allowing MPLS-based provisioning of lower-layer services such as Ethernet connections at Layer 2. Proponents of MPLS-TP also tout the following benefits for carriers and service providers that already have MPLS cores:
PBB-TE advantages. A competing proposal is PBB-TE, based originally on Nortel's proprietary Provider Backbone Transport (PBT) but now undergoing standardization within the IEEE's 802.1Qay working group. Unlike MPLS-TP, PBB-TE only supports Ethernet, meaning that other Layer 2 services must be tunneled within MPLS or converted via a gateway. Proponents of PBB-TE tout the following benefits:
It's too soon yet to say which approach will ultimately win out, but the existence of both specs spells good news for users. Both standards offer carriers the opportunity to achieve lower operating costs while improving service delivery. And that means that Carrier Ethernet services users are growing to love will be more widely-available than ever in coming years.
The enterprise appetite for Carrier Ethernet services appears to be insatiable. After a slow start in 2004 to 2006, use of various flavors of Ethernet services has skyrocketed to a whopping 73% across all industries (see chart below). Usage of Ethernet services is up even more dramatically in some sectors, including higher education, and state and local government.
What's driving the demand? In a nutshell, telecom service providers understand that enterprises perceive Carrier Ethernet to be a "cheap and cheerful" service: low-cost, high-bandwidth, easy to manage, and the ultimate in flexibility. Specifically, enterprises continue to grapple with flat or declining IT budgets. Eighty percent of companies benchmarked by Nemertes Research in the spring of 2009 (see chart below) say their IT budgets are flat to declining, and 70% said Ethernet's cost justified its deployment.
Yet at the same time, bandwidth requirements continue to rise (an average of 34% year-over-year in 2009). What's driving the growth? Increased reliance on collaborative applications across a distributed user base, for one -- meaning that users increasingly share data across the WAN. These are often multimedia applications, including video conferencing and video streaming, and thus require extremely high bandwidth and low latency. Data center consolidation driving Ethernet services Another Ethernet services driver is data center consolidation. As companies continue to consolidate data centers from a dozen to two or three, servers that used to be down the hall from users are now across the WAN, which increases requirements for both bandwidth and performance. So one clear driver for Carrier Ethernet services is the need for low-cost, high-quality bandwidth, both to link data centers together and to link larger branch offices to the data centers. Carrier Ethernet offers enterprises QoS shortcut Another driver is perceived simplicity. One of the benefits of most flavors of Carrier Ethernet is that they don't require enterprises to share routing information with the carrier. In fact, some enterprises don't even bother with routing across the WAN: They hook up switches directly to the Ethernet pipe, although this approach doesn't scale particularly well. It's also worth noting that enterprises sometimes seek to ensure quality of service (QoS) by simply throwing bandwidth at the problem. Carrier Ethernet makes that easy by providing high-bandwidth connectivity. Fully half of all multi-protocol label switching (MPLS) users don't use any QoS whatsoever -- despite the fact that the ability to ensure QoS is part of MPLS's raison d'etre. Why do folks avoid using QoS? Quite simply, it's complex. Most of the companies we work with require multiple attempts before they get the correct mappings among applications, users, sites and QoS. So short-circuiting the challenge of QoS complexity is yet another advantage of Carrier Ethernet. The Carrier Ethernet services opportunity Here's how carriers can capitalize on the growing interest in Ethernet services.
In summary, carriers should capitalize on the thirst for Ethernet services by making their offerings even easier to use and more widely available.
Metro area networks have come a long way since the leased lines and SONET rings of yore. True, they are still widely deployed and extremely versatile technologies, but as user applications increasingly feature voice and data convergence and high-bandwidth/low-latency requirements, carriers are changing their metro area networks to support these applications. To understand how metro area networks are evolving, it makes sense to examine enterprise network architectures and the applications they need to support. Enterprise WANs connect three distinct types of sites, according to Nemertes analyst Katherine Trost:
Metro area networks are most commonly used to connect sites at the "top tier" of the WAN, which includes data centers, contact centers, administrative headquarters and some (but not all) distributed offices. These tier 1 sites are typically geographically close, and the applications located there generally move massive volumes of data. As a result, they need very low latency and very high reliability. Tier 1 WAN sites are perfect for metro area networks based on technologies including dedicated fiber, dense wave-division multiplexing (DWDM) and, more and more often, Carrier Ethernet.
Carrier Ethernet suited for data center replication and call centers Data center storage replication is one of the most common applications at this tier of the WAN. Enterprises continue to consolidate multiple data centers down to a handful, then use data center replication between two or three data centers to ensure reliability and redundancy. Often, two data centers will replicate synchronously over the metro area, typically using Fibre Channel as the core communications protocol. The theoretical maximum length of a synchronous Fibre Channel connection is on the order of 120 miles (depending on the bandwidth of the link). But latency is typically the primary gating factor, and the maximum practical distance for synchronous replication is roughly 30 miles. Options for synchronous connection include Fibre Channel over SONET, Fibre Channel over DWDM and, potentially, Fibre Channel over Ethernet (FCOE). But future deployment of FCOE across the WAN will depend largely on the degree to which FCOE achieves acceptance within the data center, and here a large question mark remains. We found near-zero adoption of FCOE within data centers, with low planned usage for the next 24 months. Another common metro-area application is connectivity into contact centers (call centers), which may handle hundreds of thousands of phone calls simultaneously. As enterprises move toward a converged voice and data architecture, incoming calls are carried across the WAN rather than across dedicated voice private lines, as they were previously. But ordinary WAN services such as Multi-protocol Label Switching (MPLS) may suffer from route-convergence problems: If a logical link fails, it may require multiple seconds for the network to re-establish connectivity. For most traffic, this isn't a problem, but an outage of several seconds is long enough to cause callers to a contact center to hang up in frustration. With Carrier Ethernet, however, the connections can be engineered at layer 2, avoiding the route-convergence problem altogether. So service providers are increasingly turning to Carrier Ethernet and other technologies that support both voice and data and also can provide real-time redundancy. The growth of high-bandwidth applications in the metro Administrative headquarters often require metro-area connectivity, particularly in organizations (such as higher education institutions and state and local government) where many offices are in close proximity in a campus environment. Here, too, we see a greater-than-typical use of Carrier Ethernet (virtually all of the organizations Nemertes works with in both verticals have some degree of Ethernet in use in their metro-area networks). The use of Carrier Ethernet is likely to grow as high-bandwidth applications like video conferencing, telepresence, streaming video and distance learning increase. The use of these applications is rising steeply today, driven by several related (but not identical) trends:
The common theme across all these applications and WAN architectures is Ethernet. As voice and data converge, and as Ethernet becomes as widely deployed within data centers as Fibre Channel, Carrier Ethernet becomes the logical way to achieve high-bandwidth, low-latency links across the metro area. And those enterprises that deploy it, love it: Seventy-nine percent say they're "extremely happy" with their Ethernet deployments, and the vast majority say they expect to deploy more Carrier Ethernet in the near future (see graphic). The bottom line is that we have seen the future of metro-area networks, and it's increasingly Carrier Ethernet. Low-latency, high-bandwidth, "cheap and cheerful" Ethernet services meet the needs of those tier 1 WAN sites that are close enough together to be served by a metro-area network. About the authors: Irwin Lazar is the vice president for Communications Research at Nemertes Research, where he develops and manages research projects, develops cost models, conducts strategic seminars and advises clients. His background is in network operations, network engineering, voice-data convergence and IP telephony. He is responsible for benchmarking the adoption and use of emerging technologies in the enterprise in areas including VOIP, unified communications, Web 2.0 initiatives, social networking, and collaboration. Johna Till Johnson is the president and senior founding partner of Nemertes Research. She has decades of experience in IT structure, processes and organizations, and has worked closely with senior IT executives at leading organizations across a broad range of industries. A highly regarded expert, Ms. Johnson regularly speaks at trade shows, conferences and seminars.
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